ArcaMax

DEAR DR. ROACH: In several of your columns, either you or a reader has brought up the subject of ivermectin as a treatment for infections or cancer. Is this the same ivermectin that is in my dog's heartworm medication? The label on the dog medication says ivermectin/pyrantel. If it is the same, is it really safe for us humans? -- L.M.H.

ANSWER: Ivermectin is prescribed for humans and is approved by the Food and Drug Administration for the treatment of certain parasitic infections. Pyrantel is a separate antiparasitic drug that is used for both humans and dogs. The dose for dogs depends on their weight but is much less than the doses used for adult humans for the treatment of serious parasitic infections, like strongyloides.

When used at the correct dose, ivermectin is an effective treatment for many parasitic infections, but people should not use animal doses, even if the medication strength is the same, as they are not formulated for humans. The excipients (the nondrug components of a pill) in animal medications are potentially toxic to humans.

During the pandemic, there were many ivermectin poisonings (which was eventually shown not to be helpful for COVID-19) among people who were using preparations that were intended for external use on horses. Please don't ever use veterinary medications for humans.

DEAR DR. ROACH: I'm a 70-year-old male who has had several medical issues over the past few years, including a viral infection from 10 years ago that took months to be identified and treated. I also had a blood staph infection in 2024 that had me hospitalized for four weeks. The latter infection required surgery on my spine in the neck area to remove the infection, and several disks were fused, along with four weeks of physical and occupational therapy.

The results of the above conditions impacted my heart negatively with my ejection fraction (EF) now in the mid 30s. I've been asymptomatic during this time except for a heavy feeling in my legs. I've been taking meds to treat heart failure and minimize stress/work on my heart.

My cardiologist team has suggested getting an automated implantable cardiac defibrillator. I was advised that there was little risk and that the device would be similar to having an EMT on my shoulder with an automated external defibrillator to timely treat any cardiac "incident." Your thoughts on having the ICD implanted? -- S.W.

ANSWER: ICDs have been proven to reduce the risk of sudden death in people with severe heart failure. The EF is a measure of how much blood is ejected from the left ventricle during every stroke, with normal being between 50% to 70%. A very low EF means that the left ventricle simply can't do its job.

People with severe heart failure are at risk for sudden disturbances in rhythm, which can lead to sudden death. The ICD, which is completely implanted under the skin, can recognize a serious arrythmia and quickly give an electric shock to stop the abnormal rhythm.

The decision to place an ICD isn't trivial. While it is usually recommended for a person with an EF below 30% (35% in some cases), the cardiologist will normally start medications to help the heart. These medicines improve symptoms and prolong life when used wisely.

A person who is treated optimally with medications but continues to have symptoms, as well as a low EF, might be recommended an ICD, but I can't fully answer your question because I don't know why your heart isn't doing its job. An ICD decision is somewhat different because it depends on the underlying cause. Just the surgeries and infections shouldn't cause a low EF.

Prolonged bed rest can cause heart failure symptoms due to "cardiac deconditioning," but in these cases, the EF is usually normal. It may be that the virus caused damage to your heart, which sometimes happens. Still, if your cardiologist is recommending an ICD, I am extremely reluctant to recommend against it.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.

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